Mark_D. From Canada, joined Aug 2001, 1447 posts, RR: 5 Reply 2, posted (12 years 1 month 1 week 6 days 11 hours ago) and read 2240 times:
I don't know, and it'd take some doing (money incentives, etc.) to arrange for some kind of comprehensive testing 'bout that
But who'd you hear that from, about the Caravelle, and 752. I imagine any of the older and/or lower-cruising speed airliners glide the best, just from better lift from the less-swept-back wings. I reckon the Dornier 328 Jet would glide pretty darn well, for instance.
(and then of course there are all the turboprops to consider. You mention "airliner" so I'm not sure if you're excluding 'em entirely)
SouthernCRJ From Argentina, joined Sep 2001, 180 posts, RR: 3 Reply 4, posted (12 years 1 month 1 week 6 days 10 hours ago) and read 2215 times:
I think you're probably right, the turboprops must glide
better than jetliners.
I took the data about the Caravelle and the 752 from
a magazine. They were probably talking about jetliners.
Anyway they said that one of the prototypes of the Caravelle flown between Paris and Dijon (265 km) with the engines at idle.They also said that actually its glide ratio can only be achieved by the 752 (but they don't said which was that glide ratio)
Prebennorholm From Denmark, joined Mar 2000, 6128 posts, RR: 55 Reply 13, posted (12 years 1 month 1 week 6 days 6 hours ago) and read 2110 times:
There is very little difference between gliding ratio (or lift/drag ratio) of different airliners.
They were all made to transport the maximum payload as far as possible spending as little fuel as possible.
They all have a gliding ratio very close to 20.
The physical aerodynamic laws involved have been known very well during the last 50+ years.
Some planes have a more generous wing loading. For instance a Caravelle 3 at MTOW has a wing loading of 64lb/sq.ft. while the same value for an A320-200 is almost double at 123lb/sq.ft. It doesn't mean that the Caravelle will glide much further from the same altitude, but it will have its best gliding ratio at a slower speed. It will glide roughly the same distance, but spend longer time doing so.
The great improvements in that period were in engine technology meaning less fuel and more payload or longer range. And stronger and lighter airframe structure meaning more payload and/or more fuel for longer range.
Put a pair of RR RB211-535 on a Boeing B-47 bomber from 1948, and performance will practically copy a 757 of today.
Regards, Preben Norholm
Always keep your number of landings equal to your number of take-offs, Preben Norholm
Cedarjet From United Kingdom, joined May 1999, 7804 posts, RR: 54 Reply 15, posted (12 years 1 month 1 week 5 days 16 hours ago) and read 2070 times:
Interesting stuff. Just off the top of my head, I'd put money on the A330 having the best gliding performance, those huge graceful wings look like they really FLY. It's the (British) Airbus wing that really makes those planes sell (and the financing of course). FBW increases efficiency (and weight) by a tiny amount (like, 0.5%) but when you read about seat-mile costs being 5% better than the equivalent Boeing, it's the brilliant Airbus wing that makes the difference.
Although I bet the 777 has good characteristics, those wings from the cabin look like those high altitude spy planes' wings (Gary Powers got shot down in one), you know, the incredibly long thin straight wings, black aircraft?
fly Saha Air 707s daily from Tehran's downtown Mehrabad to Mashhad, Kish Island and Ahwaz